Communication of data between remotely-positioned sending and receiving stations is a necessary adjunct of modern society. A wide variety of different types of communication systems have been developed and are regularly utilized to effectuate communication of data between the sending and receiving stations.
Communication technology advancements have permitted the development, and commercial implementation, of new types of communication systems. Radio communication systems are exemplary of communication systems which have benefited from the advancements in communication technologies. Improvements to existing types of radio communication systems, as well as new types of radio communication systems, have been made possible as a result of the advancements in communication technologies.
Use of a radio communication system inherently permits increased communication mobility in contrast to use of a conventional wireline communication system. Communication channels defined between sending and receiving stations of a radio communication system are defined upon radio links formed therebetween. The communication channels are referred to as radio channels and do not require fixed connections for their formation.
The advancements in communication technologies which have permitted the development and implementation of new types of communication systems include, for instance, digital communication techniques. The use of digital communication techniques permits the communication capacity of a communication system to be increased as well as also to improve the quality levels of communications effectuated in the communication system.
Information which is to be communicated in a digital communication system is digitized. Once digitized, the digitized information is formatted, such as into packets of data, referred to as data packets. Data packets are sent by a sending station upon the radio channel to the receiving channel, thereby to effectuate the communication of the data packets therebetween. Individual ones, or groups, of the packets can be communicated at discrete intervals, and, once communicated, the packets of data can be concatenated together to recreate the informational content of the transmitted information.
Because the packets of data can be sent at discrete intervals, a radio, or other, communication channel need not be dedicated solely for the communication of data pursuant to a single communication session between one sending station and one receiving station. A dedicated channel, in contrast, is required in conventional circuit-switched communications. In packet-switched communications, a single channel can be used pursuant to the effectuation of a plurality of different communication sessions. Improved communication capacity is possible due to the shared nature of the communication channels permitted in packet-switched communications.
A wireless mesh network is a radio communication system which can be constructed to provide for the communication of packet data pursuant, e.g., to a digital communication technique. A wireless mesh network typically includes a plurality of nodes, each node capable of communicating with at least one other node. A wireless mesh network is implemented, for instance, as a fixed broadband access network capable of communicating broadband data between fixed-site communication stations which form the nodes. A moving ad-hoc mesh network is also representative of a wireless mesh network.
Network synchronization is necessary in a wireless mesh network to properly utilize the radio resources available to communicate thereon. Transmission and reception scheduling is conventionally utilized in a wireless mesh network. Scheduling is required to ensure that the nodes of the network be synchronized in time. Through appropriate time synchronization, guard intervals separating communications upon a radio link can be reduced as the synchronization limits the amount of drifting of bursts of packet data beyond a defined transmission period. Without proper synchronization, guard intervals of increased sizes are required, thereby reducing the communication capacity upon the radio links formed between nodes of the network.
In a mesh network, a formal hierarchy is not necessarily defined. And, if a hierarchy is defined, reference distribution, pursuant to which synchronization is performed, is implemented hierarchically. Reference errors increase accumulatively in successive branches of the hierarchically-defined structure.
A manner by which to provide a systematic reference by which to effectuate time synchronization in a mesh network, such as a fixed broadband access network or a moving ad-hoc mesh network would therefore be advantageous.
It is in light of this background information related to communications in a mesh network that the significant improvements of the present invention have evolved.